Sewing machine



Oct. 22, 1940.

C. RUBEL SEWING MACHINE 5 Sheets-Sheet l INVENTOR:

Filed Feb 8. 1939 a) M m R N f m s T M A W c. k Y

Oct. 22, 1940.

C. F. RUBEL SEWT NG MACHINE Filed Feb. 8, 1939 5 Sheets-Sheet 3 WWI M M VF 0 N T [5 T D A W W w WITNESSES Oct. 22, 1940. c. F. RUBEL snwms mourns Filed Feb. 8. 1939 5 Sheets-Sheet 4 WITNESSES; A INVENTOR:

. 2 40 Charles if'fiubel/ W 91 BY @wlm A TTORNEYS.

Oct. 22, 1940. c RUBEL 4 2,219,210

SEWING MACHINE Filed Feb. 8, 1939 INVENTOR: Charles 2? [fl/ $811,

@Zffia W ATTORNEYS.

5 SheetsSheet 5 Patented Oct. 22, 1940 UNEE STATES SEWING MACHINE Charles F.- Rubel, Chicago, IlL, assignor to Union Special Machine Company, Chicago, 111., a corporation of Illinois Application February 8, 1939, Serial No. 255,193

1'7 Claims.

This invention relates to sewing machines. More particularly it has reference to lock stitch sewing machines of the types disclosed in my copending applications Serial Nos. 123,180 and.

15 ,646 filed respectively on January 30, 1937, and August 18, 1937, wherein the non-rotative bobbin carrier has capacity for limited axial movement normally relative to the rotary hook; and wherein, in order to minimize friction, heating and resultant rapid wear, a bobbin carrier control means having orbital movement by virtue of being mounted on the feed bar of the feed mechanism of the machine coacts with a cam surface or surfaces on the front of the bobbin carrier, to periodically take up the axial play of the latter for but a predetermined instant during each stitch forming cycle to preclude pinching and cutting of the needle thread loop between opposing annular bearing surfaces of said hook and bobbin carrier.

My present invention has for its chief aims to afford, through improvements, such as hereinafter fully set forth in the feed mechanism as well as in the bobbin carrier control means, firmer support for the latter so that it will not in any way be influenced by variations in'the loads to which the feed dog is intermittently subjected; and to secure this desideratum without barring ready access to the rotary hook of the sewing machine for convenience of replenishing the bobbin thread when necessary, nor to the feed dog to adjust it.

Other objects and attendant advantages will appear from the following description of the attached drawings, wherein Fig. l is a fragmentary View partly in horizontal sectional view of a rotary hook lock stitch sewing machine embodying the present improvements.

Figs2 and 3 are fragmentary cross sectional views taken as indicated respectively by the arrows 2-2 and 3-3 in Fig. 1.

Fig. is a f agmentary view of the machine partly in front elevation and partly in longitudinal section.

Fig. 5 is a fragmentary detail longitudinal sectional view of the rotary hook and the contiguous parts of the bobbin carrier control means drawn to a larger scale and taken as indicated by the arrows 55 in Fig. 1 and Fig. 6 is a fragmentary section similar to Fig. 5 but viewed in the opposite direction as indicated by the arrows 66 in Fig. 1.

Fig. 7 is a detail cross sectional view taken as indicated by the arrows 'I-I in Fig. 6.

Fig. 8 is a view like Fig. 5 .with the bobbin carrier control means differently positioned and showing how said means operates to momentarily take up the axial play of the bobbin carrier during the stitch-forming cycle.

Fig. 9 is a detail view like Fig. 7 with the rotary hook somewhat further advanced in its rotatio-n.

Fig. 10 is a detail View partly in elevation and partly in section taken as indicated by the ar- 10 rows, iii-49 in Figs. 1 and 2.

(Figs. 11 and 12. are perspective views of certain parts of the bobbin carrier control means shown in Fig. 10; and.

Fig. 13 is a perspective view of the bobbin car- 15 rier engaging member of thebobbin carrier control means.

With more specific reference first more particularly to Figs. 1-4 of the drawings, the numeral l4 designates the work support or base of the 20 sewing machine beneath which is suitably journaled a longitudinally-extending drive shaft l5 rom which the complemental stitch forming and feed mechanisms, hereinafter described, derive their movements. The needle of the machine in- 25 dicated at It in Fig. 2 is adapted to be reciprocated vertically in a well known way by suitable means, not illustrated, from above the work support M. 2

The complemental stitch forming mechanism 0 includes a short shaft H which is journaled beneath the work support M in parallel relation to the drive shaft l5 and which is driven from the latter at increased speed, through a pair of intermeshing spur gears l8'and l9. These gears 5 i8 and 29 are shown as being in the ratio of two to one so that the shaft H is caused to revolve twice for each rotation of the drive shaft, and enclosed in an 011 housing 2s integrally formed as a depending projection of the work support 40 M. Secured by set screws 2! to the outer end of the shaft ll is an axially hollow rotary hook 22 which encloses and revolves about'a bobbin carrier composed in this instanceof two parts, to wit, a bobbin case holder 23 and a bobbin case 45 24. As shown in Fig. 5, the external circumferential rib 25 of the bobbin case holder 23 is somewhat narrower than the internal circumferential groove 25 of the hook 22 so that said holder may normally have capacity for limited axial movement relative to said hook as and for the purpose set forth in the two copending applications hereinbefore referred to. The bobbin case holder 23 is however restrained against rotation with the hook 22 through engagement within a 5 frontal notch 21 at the top of its face flange 28 of a projection 29 at the end of a rotationrestraining finger 30 secured to the underside of the work support [4 by a screw 3i in the manner shown in Fig. 2. The bobbin case 24 has an inwardly projecting axial sleeve 32 which fits over an axial stud 33 within the bobbin case holder 23,-and relative rotation thereof is prevented through engagement of a notch 35 in its top with a correspondingly allocated key projection 36 on the inner periphery of said holder, see Figs. 5, '7, 8 and 9. Freely rotatable about the sleeve 32 of the bobbin case 24 within the holder 23 is a flanged spool or bobbin 3'! wound with a supply of the bobbin thread T. Above the axis of the rotary hook 22, the front face of the bobbin case 24 is formed with a sloping cam surface at 38, and at the bottom with a counter sloped cam surface at 39. These cam surfaces 38 and 39 will be again referred to later. In addition to the features already pointed out, the rotary hook 22 is provided with the usual beak 40 for seizing the loop L of the needle thread T and carrying it around the bobbin case holder 23, and with a tail 4| from which the needle loop is eventually released after having passed about said holder in the well known way.

The feed mechanism of the machine includes a feed bar which extends crosswise of the axis of the rotary hook 22 and has a depressed portion 45a which underreaches said hook as shown in Figs. 2 and 3. Supported by the feedbar 45 is a' horizontal arm 46 which overreaches the rotary hook 22 and carries a feed dog 4'! whereof the toothed'portions 48 extend upward through slots 49 in a throat plate 50 set into the Work support [4 to react upon the presser'foot of the machine shown at 5| in Figs. 2 and 3. From Fig. 2 it will be noted that the arm 48' has a square depending shank 460. which engages a vertical guide slot 52 midway of the length of the feed bar 45 to one side of the rotary hook axis, and is secured with provision for vertical adjustment of the feed dog 47, by a screw 53. Another screw 53a engaging upwardly into a lateral projection 45a of the feed bar 45 with its head underlapping the lower end of the shank 46a serves as an aid in adjusting the feed dog 41. At one end, the feed bar 45 is pivotally connected by a pin 54 to a supporting means in the form of an upright rocker 55 which is fixed upon a rock shaft 56 journaled in spaced pendant bearing lugs 5'! and 58 on the work support l4. At 'its opposite end, the feed bar 45 is pivotally connected by a pin 59 to another support in the form of an upright link 69 which is in turn pivoted at 6| to a horizontal arm 62 at one end of another rock shaft 63. As shown the rock I v shaft 63 is journaled in a bracket 65 secured 60 port M. The feed bar 45 is operated for imparby screws 66 to the underside of the work suptation of horizontal feeding, as well as up and ,down movements to the feed dog 4! from a single rotary actuator 6! (Fig. 3) affixed to the front end of the drive shaft l5, said actuator comprising a disc 68 with an eccentrically disposed crank 'pin 69. By means of a pitman in having tele- "scopically-interengaged end components 15a and 101), the rocker 55 is coupled with the crank pin 69 as best shown in Fig. 3. The sleeve component, 19a of the link 10 is pivotally connected at H to the lower end of a link or lazy bar '12 adaptedto oscillate about a pivot stud 13 at the outer end of an arm 15 which latter is secured to a regulating shaft 16 suitably journaled beneath the work support I4 and capable of rotative adjustmentby means not illustrated. Pivotally connected at one end to the sliding component 10b of the link 15 by a pin TI is a downwardly curved link 18 whereof the other end is similarly connected by a pin 19 to the top end of an upright arm 89 which is affixed to the rock shaft 63 at that end of the latter remote from the observer in Figs. 2 and 3. The operation of the feeding mechanism is exactly like that of the feeding mechanism forming the subject-matter of a copending application Serial No. 51,992

filed by the present applicant jointly with Norman V. Christensen and Clarence C. Smith on a headed screw stud 8| which engages upwardly into a downwardly projecting boss 82 on the feed bar 45 is a horizontal arm 83. Normally, this arm 83 occupies the parallel position relative to the feed bar 45 in which it is shown in full lines in the drawings. While in this position, the arm 83 is engaged in a lateral recess 85 in a boss 86at the outer side of the feed bar 45, see Figs. 2 and. 10, and locked in place by a vertical latch pin 81 which is axially slidable in v the boss 86 and which has its top end diametrically reduced to fit upwardly into a small aperture 88 of corresponding size in said arm. The latch pin 8'! is held against rotation through engagementof a lateral stud projection 89 there on with a vertical guide slot 90 in the boss 86,

and is yieldingly held in elevated position by a leaf spring 9| which is illustrated in perspective in Fig. 11. As shown, the spring 9| is of L configuration with its short vertical arm abutted against the back of the feed bar 45, and with its long horizontal arm extending forwardly beneath said bar and the boss 86 and bearing against the bottom end of the latch pin Bl. The vertical arm of the leaf spring 9| is apertured as at 92 for passage of the shank of a cap screw 93 by which it is secured to the feed bar 45; While the horizontal arm is provided with a longitudinal slot 95 to clear the shank of a small cap screw 95 which engages axially into the bottom end of the latch pin 81. The horizontal arm of the leaf spring 9| is moreover of such length as to extend beyond the boss 86 as in Figs. 1 and 11 so that it may be manipulated by pressure of a finger thereupon to withdraw the bolt 8'! and release the arm 83 for a purpose presently explained. Instead of being separately formed and secured to the feed bar 45 by the screw 93 which anchors the leaf spring 9i and another screw shown at 9'! in Fig. 10, the boss 86 may, if found to be more desirable or expedient in practice, be

made integral with said feed bar. From Figs. 1, 2,

all

bobbin case 24. From the inner face of the disc lGl extend three annularly arranged spot projections I02, 103 and IE4 which are substantially equi-spaced circumferentially as shown in Figs. '7 and 9. The projections I02, Ill-3 are semispherical and lie in a substantially horizontal plane above the axis of the rotary hook 22 opposite the inclined upper cam surface 38 of the bobbin case 2d. The projection H14 on the other hand is in the form of a short angular rib with a central point which lies substantially in the vertical plane of the hook axis opposite to the cam surface 39 on the face of the bobbin case 24. By virtue of being supported by the arm 83 on the feed bar 45, orbital movement is imparted to the disc IEH with the result that the projections I02, I03, H34 of the latter trace the irregular elliptic orbits shown in dotted lines at lfifa, lllSa and Ma, in Figs. 7 and 9, and by camming action with the face of the bobbin case 24 cause the bobbin case holder 23 to be periodically thrust inward whereby the normal free axial play of the latter is taken up momentarily during each stitch-forming cycle to prevent pinching and cutting of the needle loop thread T between the inner shoulder of the groove 25 in the rotary hook and the rib 25 on the bobbin case holder 23 in precisely the same manner as disclosed in my copending application Serial No. 159,646. The disc H3! is secured against rotative displacement on the arm 83 by a set screw I85 which bears against the disc shank me. For the purpose of facilitating axial adjustment of the disc llll relative to the rotary hook 22, there is provided an adjusting screw H36 which is threadedly engaged in the boss 58 of the arm 83 to bear against the back of said disc, see Figs. 5 and 8.

Through retraction of the disc lfil by outward swinging of the arm 83 for example to the position in which it is shown in dot-and-dash lines in Fig. 1, it will be seen that the rotary hook 22 is made accessible from the front for convenience of removing the bobbin case 24 when bobbin thread replacements become necessary. In order to facilitate this operation, a means is provided for automatically swinging the arm 83 outward upon withdrawal of the latch pin 8?. This means, see'Figs. 1 and 12, is in the form of a relatively stiff spring finger l6? which is secured by a screw its to the back of the feed bar and which engages a fiat tangential surface Hi9 on the hub of arm 83, the outward swing of the arm being limited by encounter of a stop projection H0 thereon with the free end of said spring finger. As shown in Fig. 10, "the inner side edge of the arm 83 is beveled as at ill for camming action with the rounded tip N2 of the latch pin 8?. Accordingly as the arm 33 is swung back to its normal position, the latch pin 8'? is depressed temporarily but re-latched automatically by action of the spring 9| when the aperture 88 in said arm comes into registry therewith.

Since the feed bar 35 is in itself strong and rigid and moreover since it is effectively supported at opposite ends of the rotary hook axis, it is immune against possible yielding or flexure under the varying loads and cannot therefore iniiuence the action of the bobbin carrier control means mounted thereon in the manner described so that the latter can be depended upon to operate accurately and uniformly at all times in the function which it is designed to perform. This advantage is gained without obstructing access to the rotary hook 272 from the front for bobbin thread replenishment by virtue of the downward curving of the feed bar 45a. beneath said hook. In this connection it is also to be noted that the construction of the feed bar 45 is such as to render the screws 53 and 53a readily accessible for convenience of vertically adjusting the feed dog 41.

Having thus described my invention, I claim:

1. In a sewing machine, stitch forming means including a pair of coaxial relatively rotating components which have capacity for limited endwise play; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of said components, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and means on the feed bar for periodically reducing and substantially taking up the axial play between the two components of the stitch forming means.

2. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the feed bar for periodically reducing and substantially taking up the axial play of the bobbin carrier.

3. In va sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play relative to the hook; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, and underreaching said hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the feed bar to periodically reduce and substantially take up the axial play of the bobbin carrier.

4. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, a rotary actuator disposed to one side of the rotary hook axis from which the supporting means are actuated to impart horizontai :1

feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the feed bar to periodically reduce and substantially take up the axial play of the bobbin carrier.

5. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relativeto the hook; feed mechanism including a bar extending crosswise of the hook axis and underreaching the hook, an arm on the bar overreaching the hook, a feed dog carried by the arm, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the bar for periodically reducing and substantially taking up the axial play of the bobbin carrier.

6. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook; feed mechanism including a bar extending crosswise of the hook axis and underreaching the hook, a feed dog on the bar overreaching the hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the bar for periodically reducing and substantially taking up the axial play of the bobbincarrier.

7. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook; feed mechanism including a bar extending crosswise of the hook axis and underreaching the hook, an arm secured with capacity for vertical adjustment to the bar and overreaching the rotary hook, a feed dog mounted on said arm, means supporting the bar at opposite ends, and means for actuating the supporting means to impart horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the bar for periodically reducing and substantially taking up the axial play of the bobbin carrier.

8. In a sewing machine, a drive shaft, stitch forming mechanism including a rotary hook, an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook, and a shaft for the hook extending parallel to the drive shaft; gearing by which the hook shaft is driven from the drive shaft; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the hook shaft, means supporting the bar at opposite ends, a rotary actuator on the drive shaft, and intermediate connections between the rotary actuator and the bar supporting means whereby horizontal feeding movements and up and down movements are imparted to the bar; and bobbin carrier control means mounted on the feed bar for periodically reducing and substantially taking up the axial play of the bobbin carrier.

9. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook, said carrier having a cam surface on its outer face; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means mounted on the feed bar and receiving orbital movement therefrom to cooperate with the cam surface on the bobbin carrier to periodically reduce and substantially take up the axial play of the latter.

10. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook, said carrier having cam surfaces on its outer face; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means including a member mounted on the feed bar and receiving orbitalsmovement therefrom, said member having a plurality of circum ferentially-arranged spot projections adapted, by rubbing contact at corresponding regions with the cam surfaces on the bobbin carrier to periodically reduce and substantially take up the axial play of the latter.

11. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook, said carrier having a cam surface on its outer face; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means including a lever pivoted on the feed bar and having a projection on its outer end receiving orbital movement from said bar and coacting with the cam surface on the bobbin carrier to periodically reduce and substantially take up the axial play of the latter, a latch by which the lever is normally locked to the bar, a spring tongue operative upon withdrawal of the latch by coaction with a cam surface on the lever tangential to the pivot to automatically swing said arm outwardly away from the rotary hook for convenience of access to the bobbin carrier, and a stop shoulder on the lever to limit its outward swing by engagement with the end of said spring tongue.

12. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook, said carrier having a cam surface on its outer face; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, and means for imparting horizontal feeding movements and up and down movements to the bar; and bobbin carrier control means including a lever pivoted on the feed bar and having a projection on its outer end which receives orbital movement from said bar and coacts with the cam surface on the bobbin carrier to periodically reduce and substantially take up the axial play of the latter, a latch pin slid-able in the feed bar, and a leaf spring secured to the feed bar and tending to keep the latch pin normally in engagement with :an opening in the lever to lock it to the feed bar, said spring having an actuating finger projection whereby it may be flexed to release the latch pin and thereby permit retraction of the lever away from the rotary hook for convenience of access to the bobbin carrier.

.13. In a sewing machine, stich forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook, said carrier having a cam surface on its outer face; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook and underreaching the rotary hook, a feed dog, an arm overreaching the rotary hook whereon the feed dog is mounted, said arm having a pendant shank slidably engaged in a vertical slot in the bar to one side of the rotary hook for the purpose'of vertical adjustment of the feed dog, means accessible at the front of the bar for securing the arm in adjusted positions, and means for supporting the bar at opposite ends, means for actuating the bar to impart horizontal feed movements and up and down movements to the feed dog; and bobbin carrier control means including a lever pivoted on the feed bar and having .a projection on its outer end which receives orbital movement from said bar and coacts with the cam surface on the bobbin carrier to periodically reduce and substantially take up the axial play of the latter, tripp'able latch means for normally locking the lever to the feed bar with capacity for being swung outward away from the rotary hook for convenience of access to the bobbin carrier.

14. In a sewing machine, stitch forming means including a pair of coaxial relatively rotating components which have capacity for limited end- Wise play; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of said components, means supporting the bar at opposite ends, means for imparting horizontal feeding movements and up and down movements to the bar, and means whereby the horizontal feeding movements of the feed bar maybe increased or decreased; and means on the feed bar for periodically reducing and substantially taking up the axial play between the two components of the stitch forming means.

15. In a sewing machine, stitch forming means including a pair of coaxial relatively rotating components which have capacity for limited endwise play; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of said components, means supporting the bar at opposite ends, means for imparting horizontal feeding movements and up and down movements to the bar, and means whereby the action of the feed bar may be reversed; and means on the feed bar for periodically reducing and substantially taking up the axial play between the two components of the stitch forming means.

16. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, means for imparting horizontal feeding movements and up and down movements to the bar, and means whereby the horizontal feeding movements of the feed bar may be increased or decreased; and means on the feed bar for periodically reducing and substantially taking up the axial play between the bobbin carrier and the rotary hook.

17. In a sewing machine, stitch forming mechanism including a rotary hook and an associated non-rotating bobbin carrier capable of limited axial play normally relative to the hook; feed mechanism including a feed dog carrier in the form of a bar extending crosswise of the axis of the rotary hook, means supporting the bar at opposite ends, means for imparting horizontal feeding movements and up and down movements to the bar, and means whereby the action of feed may be reversed; and bobbin carrier control means mounted on the feed bar for periodically reducing and substantially taking up the axial play of the bobbin carrier.

CHARLES F. RUBEL. 

